Igneous Rocks Composition, Texture and Classification, Description and Occurrence

Occurrence, Texture, and Classification of Igneous Rocks

Magma Composition and Igneous Rocks

Introduction In the following chapters we will find that nearly all of the varied aspects of volcanism are either directly or indirectly controlled by the chemical composition of magma and the rate at which it cools and solidifies. If you are to understand and appreciate subsequent discussions of volcanoes and related volcanic phenomena, it is essential that you have a good grasp of the basic c...

AGeochemical Classification for Feldspathic Igneous Rocks

In this paper we classify the range of feldspathic igneous rocks using five geochemical variables: the FeO/(FeOþMgO) ratio or Fe-index, the modified alkali^lime index, the aluminum-saturation index, the alkalinity index, and the feldspathoid silica-saturation index.The Fe-index distinguishes between melts that have undergone extensive iron enrichment during differentiation from those that have ...

Description and classification of soils and rocks

These broad generalizations are, of course, limited in accuracy. But they give the geotechnical engineer a good basis on which to consider, at the start of a project, both the likely construction problems and the methods of investigation which might be used. In practice, it is found that the ground varies continuously beneath a site, and it is not often possible to find sharp transitions from o...

Extra-terrestrial igneous granites and related rocks: A review of their occurrence and petrogenesis